CHAPTER ONE

1.0 INTRODUCTION/LITERATURE REVIEW

All cells, at least those that are metabolically active, contain approximately 85.95% water, it

is therefore a truism to state that any environmental factor that affects, the activity,

structure or physical state of water poses a threat to life in one’s health. Oceans have

historically been the dumping grounds for the wastes from society. Fortunately, this view

has changed and regulations have become much more stringent, but the effects of the past

still lingers. Pollution has been very damaging to aquatic ecosystems, and may consist of

agricultural, urban, and industrial wastes containing contaminants such as sewage, fertilizer,

and heavy metals that have proven to be very damaging to aquatic habitats and species.

Many of the pollutants entering aquatic ecosystems (e.g., mercury, lead, pesticides, and

herbicides) are very toxic to living organisms (USEPA, 2007). They can lower reproductive

success, prevent proper growth and development, and even cause death. The organisms

that are most directly and adversely affected by toxic pollutants consist of larvae, eggs, and

other organisms that live at the surface or near the bottom of aquatic habitats where

pollutants tend to settle. Filter feeders (e.g., clams, and mussels) and other organisms

higher up in the food chain (e.g., swordfish, tuna) are also affected by the presence of

toxicants. Filter feeders and predatory fin-fish are not directly affected by the presence of

toxic chemicals in the water column or sediments, instead they bioconcentrate and

bioaccumulate the toxicants. For example, humans, animals, and birds have been known to

suffer from mercury poisoning, lead poisoning, and other neurological diseases from eating

fish and shellfish that are contaminated with high levels accumulated toxicants.

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In addition to toxic pollutants, increased nutrients, especially nitrogen and phosphorus,

from city sewage and fertilizers from agricultural areas (e.g. animal feed lots) have also

proven to be very damaging to aquatic ecosystems. Certain levels of these nutrients are

known to cause harmful algal blooms in both freshwater and marine habitats. In turn, algal

blooms impact aquatic biodiversity by affecting water clarity, depleting oxygen levels, and

crowding out organisms within an ecosystem. In some instances algal blooms have

produced neuro-toxins that have led to species die-offs and illnesses such as Paralytic

shellfish poisoning. Other pollutants affecting biodiversity in aquatic ecosystems are solid

pollutants like plastic bags, plastic rings, abandoned fishing gear, and other man-made

materials that result from garbage dumped from shore and ships. Trash and debris of this

nature floating in aquatic environments, have been known to entangle and even kill marine

mammals and birds. Animals such as sea turtles have often died through ingesting bits of

plastic and other discarded materials. In addition, abandoned fishing gear such as lobster

pots and nets are self-baiting and will continue to catch and kill fish and other organisms for

years after the gear has been discarded or lost (USEPA, 2007).

1.1 INLAND WATER

Inland water systems can be fresh or saline within continental and island boundaries. They

include lakes, rivers, ponds, streams, groundwater, springs, cave waters, floodplains, as well

as bogs, marshes and swamps, which are traditionally grouped as inland wetlands. The

biodiversity of inland waters is an important source of food, income and livelihood,

particularly in rural areas in developing countries. Other values of these ecosystems include:

water supply, energy production, transport, recreation and tourism, maintenance of the

hydrological balance, retention of sediments and nutrients, and provision of habitats for

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various fauna and flora. But since all terrestrial animals and plants depend on fresh water,

the boundaries between aquatic and terrestrial are blurred. At the species level, inland

water biodiversity generally includes all life forms that depend upon inland water habitat for

things other than simply drinking (or transpiration in plants). Besides the obvious life living

within water itself (e.g., fish), this also includes many “terrestrial” species of animals (e.g.,

water birds), semi-aquatic animals (e.g., hippopotamus, crocodiles, and beaver) and plants

(e.g., flooded forest, mangroves, vegetation associated with the margins of water bodies).

The majority of amphibians, for example, breed in fresh water. As for all biodiversity, for

inland waters the concept includes diversity at the species, genetic and ecosystem level.

Species which are restricted to inland waters (e.g., freshwater fish) cannot move easily

between different areas. Inland waters are therefore characterized by high endemicity of

freshwater species – for example between different lakes or the upper reaches of sub-

catchments of rivers, often even where located physically close to each other. This is also

reflected in high levels of genetic diversity. Most importantly, ecosystem diversity (including

hydrological and physical diversity within the landscape) is an extremely important aspect of

the biodiversity of inland waters. This ecosystem diversity is very complex and includes both

aquatic and terrestrial (landscape) influences; maintaining it is critical to maintaining

ecosystem services. Also, human interventions in the ecosystem tend to deliberately reduce

this diversity (e.g., by modifying the form, and therefore function, of river channels and/or

hydrology).

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1.2 LAGOON POLLUTION

Lagoons have a less well defined drainage network and larger open areas and are usually

shallow—often less than 2 m (6.5 ft) deep. A raised ridge, or sand barrier, is characteristic

of lagoons. This feature was formed during the interglacial stage of the Pleistocene Epoch,

some 80,000 years ago, when sea shorelines were about 6 m (20 ft) above present average

levels. During the last ice age, fluvial and atmospheric processes eroded the earlier coast.

When sea levels rose anew, the areas behind the barrier were once again flooded. Lagoons

are present on all continents (Encarta 2008). Water pollution may come from point sources

or nonpoint sources. Point sources discharge pollutants from specific locations, such as

factories, sewage treatment plants, and oil tankers. The technology exists to monitor and

regulate point sources of pollution, although in some areas this occurs only sporadically.

Pollution from nonpoint sources occurs when rainfall or snowmelt moves over and through

the ground (USEPA).

1.2.1 POINT SOURCE POLLUTION

Point source pollution refers to contaminants that enter the lagoon through a discrete

conveyance, such as a pipe or ditch. Examples of sources in this category include discharges

from a sewage treatment plant, a factory, or a city storm drain. The U.S. Clean Water Act

(CWA) defines point source for regulatory enforcement purposes

1.2.2 NON-POINT SOURCE POLLUTION

Non-point source (NPS) pollution refers to diffuse contamination that does not originate

from a single discrete source. NPS pollution is often a cumulative effect of small amounts of

contaminants gathered from a large area. Nutrient runoff in stormwater from “sheet flow”

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over an agricultural field or a forest is sometimes cited as examples of NPS pollution.

Contaminated stormwater washed off of parking lots, roads and highways, called urban

runoff, is sometimes included under the category of NPS pollution. However, this runoff is

typically channeled into storm drain systems and discharged through pipes to local surface

waters, and is a point source. The CWA definition of point source was amended in 1987 to

include municipal storm sewer systems, as well as industrial stormwater, such as from

construction sites.

FIGURE 1.1

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1.3 PARAMETERS OF INTEREST

The parameters considered in determining the quality of water are many and varied. The

choice of parameters therefore rests on the researcher’s interest and objectives.

Possible choice of parameters may be centered on the following:

Geographical location

Economic activities

Source of pollution

Availability of appropriate instrument and reagent.

This project would focus on the conventional and nutrient parameters.

1.4 CONVENTIONAL/PHYSICAL PARAMETERS

pH

Temperature

TDS

Turbidity

Conductivity

Salinity

1.4.1 NUTRIENT PARAMETERS

These parameters are the result of life activities in the lagoon. They provide the nutrient

requirement of organisms and such explain why life may exist in water. They include:

Nitrate Phosphate Sulphate

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1.5 SPECTROPHOTOMETRY

In spectrophotometer analysis, a source of radiation is used that extends into the ultraviolet

region of the spectrum. The instrument employ is the spectrophotometer. It consists of two

components;

An optical spectrometer- it is an instrument possessing an optical system which can

produce dispersion of incident electromagnetic radiation, and with which

measurements can be made of the quantity of transmitted radiation at selected

wavelengths of the spectral range.

A photometer is a device for measuring the intensity of transmitted radiation or a

function of this quantity.

The variation of the colour of a system with change in concentration of some components

forms the basis of calorimetric analysis. The colour is usually due to the formation of a

coloured compound by the addition of an appropriate reagent.

Colorimetry is concerned with the determination of the concentration of a substance by

measurement of the relative absorption of light with respect to a known concentration of

the substance.

1.5.1 BEER-LAMBERT’S LAW

The law states that there is a logarithmic dependence between the transmission (or

transmissivity), T, of light through a substance and the product of the absorption coefficient

of the substance, α, and the distance the light travels through the material (i.e. the path

length), ℓ. The absorption coefficient can, in turn, be written as a product of either a molar

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absorptivity of the absorber, ε, and the concentration c of absorbing species in the material,

or an absorption cross section, σ, and the (number) density N of absorbers.

For liquids, these relations are usually written as

Whereas for gases, and in particular among physicists and for spectroscopy and

spectrophotometry, they are normally written

Where I0 and I are the intensity (or power) of the incident light and that after the material,

respectively

The transmission (or transmissivity) is expressed in terms of an absorbance which for liquids

is defined as

Whereas for gases, it is usually defined as

This implies that the absorbance becomes linear with the concentration (or number density

of absorbers) according to

8

And

For the two cases, respectively

Thus, if the path length and the molar absorptivity (or the absorption cross section) is

known and the absorbance is measured, the concentration of the substance (or the number

density of absorbers) can be deduced.

Although several of the expressions above often are used as Beer–Lambert law, the name

should strictly speaking only be associated with the latter two. The reason is that

historically, the Lambert law states that absorption is proportional to the light path length,

whereas the Beer law states that absorption is proportional to the concentration of

absorbing species in the material.

If the concentration is expressed as a mole fraction i.e. a dimensionless fraction, the molar

absorptivity (ε) takes the same dimension as the absorption coefficient, i.e. reciprocal length

(e.g. cm−1). However, if the concentration is expressed in moles per unit volume, the molar

absorptivity (ε) is used in L·mol−1·cm−1, or sometimes in converted units of mol−1 cm2.

The absorption coefficient α' is one of many ways to describe the absorption of

electromagnetic waves. For the others, and their interrelationships, see the article:

Mathematical descriptions of opacity. For example, α' can be expressed in terms of the

imaginary part of the refractive index, κ, and the wavelength of the light (in free space), λ0,

according to

9

In molecular absorption spectrometry, the absorption cross section σ is expressed in terms

of line strength, S, and an (area-normalized) line shape function, Φ. The frequency scale in

molecular spectroscopy is often in cm−1, wherefore the line shape function is expressed in

units of 1/cm−1, which can look funny but is strictly correct. Since N is given as a number

density in units of 1/cm3, the line strength is often given in units of cm2cm−1/molecule. A

typical line strength in one of the vibrational overtone bands of smaller molecules, e.g.

around 1.5 μm in CO or CO2, is around 10−23 cm2cm−1, although it can be larger for species

with strong transitions, e.g. C2H2. The line strengths of various transitions can be found in

large databases, e.g. HITRAN. The line shape function often takes a value around a few

1/cm−, up to around 10/cm−1 under low pressure conditions, when the transition is Doppler

broadened, and below this under atmospheric pressure conditions, when the transition is

collision broadened. It has also become commonplace to express the linestrength in units of

cm−2/atm since then the concentration is given in terms of a pressure in units of atm. A

typical linestrength is then often in the order of 10−3 cm−2/atm. Under these conditions, the

detectability of a given technique is often quoted in terms of ppm•m.

The fact that there are two commensurate definitions of absorbance (in base 10 or e)

implies that the absorbance and the absorption coefficient for the cases with gases, A' and

α', are ln 10 (approximately 2.3) times as large as the corresponding values for liquids, i.e. A

and α, respectively. Therefore, care must be taken when interpreting data that the correct

form of the law is used.

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The law tends to break down at very high concentrations, especially if the material is highly

scattering. If the light is especially intense, nonlinear optical processes can also cause

variances.

Figure 1.2

Diagram of Beer–Lambert absorption of

a beam of light as it travels through a

cuvette of width ℓ.

1.5.2 CALIBRATION OF THE SPECTROPHOTOMETER

The spectrophotometer is operated by first of all standardizing the instrument with the

respective chemical. A given number was entered on the instrument. After which it

displayed a wavelength with respect to the parameter of interest. The instrument was then

turned to the wavelength and the necessary parameter concentrations were then read after

treating the samples with the appropriate reagent.

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1.6 CONVENTIONAL PARAMETERS

1.6.1 pH

pH is probably the most commonly measured quantity on environmental research and

water quality control. This expresses the acidity or basicity of a solution. The concentration

of hydrogen in solution determines the pH. It’s expressed mathematically as:

An acid is a substance that produces hydrogen ion in an aqueous solution. A base is a

hydroxyl ion in an aqueous solution. In acidic water, more acid materials are present.

Alkalinity is the condition in which more alkaline or basic materials are present. Acidic water

has to be less than 7.0, with neutral at a pH of 7.0. Alkaline water has pH greater than 7.0.

Acidity and alkaline are determined with various colorimetric papers, pH meters or titration

devices.

1.6.2 TEMPERATURE

Temperature affects the density and stratification of the water. It affects density and

viscosity of sediment transportation, vapour pressure on evaporation rates, and partial

pressures of gases on gas solubility, particularly oxygen and its impact on aeration.

Temperature affects many physical properties of water, the solubility of dissolved gases and

the toxicity of many other parameters. The rate of evaporation increases as the

temperature rises and water vapour pressure increases. It is important that an adequate

oxygen supply is present in the water because most living organisms depend on oxygen in

one way or the other.

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1.6.3 TDS (Total Dissolved Solids)

It is a measure of the total dissolved solids in a water sample. The dissolved solids are most

readily changed by biological, chemical or physical processes. The concentration of dissolved

solids is directly related to the conductivity.

The quantity of TDS in a body of water depends on several factors including:

Precipitation contributing to the body of water

The type of soil and rock the water passes over and human activities.

The major dissolved substances found in water that can cause the above problems are

positively charged ions of Na, Ca, Mg, K, and Fe, and anions such as CI¯, HCO₃¯, CO₃²¯ and

SO₄²¯. High levels of TDS may cause objectionable taste and laxative effect on animals. An

excessive level of TDS in water also leaves the water unsuitable for irrigation purposes. It

also causes foaming and may corrode some metals.

1.6.4 TURBIDITY

It is a measure of the clarity of water. Turbidity is the presence of suspended materials such

as clay, silts, finely divided organic materials, plankton and other inorganic material.

Turbidity although not a hazard itself, may be an indication that pollution has been

introduced into the water. High levels of turbidity decrease the amount of oxygen coloration

and taste, which is not characteristic of quality water. It may also cause irritation of the

throat.

1.6.5 CONDUCTIVITY

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The electrical conductivity measurement of a solution determines the ability of the solution

to conduct an electrical current. The electrical conductivity of water is directly related to the

concentration of dissolved salts and anions. The dissolved ions increase the ability of water

and aqueous solution to transfer electrons and as a result conduct electricity. Accordingly,

conductivity meters are used to measure the electrical conductivity of water. A factor that

determines the degree to which water will carry an electrical current includes;

Concentration

Mobility of ions

Oxidation state

Temperature of water

High levels of dissolved solids can cause mineral tastes in drinking water. Also, water high in

dissolved solids corrodes metal surfaces.

1.7 NUTRIENT PARAMETERS

1.7.1 NITRATES

Nitrates impart a bitter taste to water at levels of 20 to 50ppm. Nitrate levels of about

25ppm often indicate contamination of lagoons from human sources such as animal waste,

inorganic compounds and chemical fertilizers.

Nitrates are converted within the body to nitrates by bacterial action. The nitrates react

with haemoglobin to cause a condition known as methemoglobinemia, in which

haemoglobin loses the ability to carry oxygen. This is particularly better growth conditions

for the bacteria.

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1.7.2 PHOSPHATES

Phosphorous is closely associated with water because of its use in the production of algae

blooms. Phosphorous exists commonly in the oxidized state. Most waters generally contain

low levels of phosphorous (approximately 0.01-0.5mg/l). The primary source of

phosphorous in water is of geologic origin.

The main sources of phosphate in lagoons include;

Fertilizers

Sewage

Detergents

And rain water

Phosphates are not toxic people or animals unless they are present in very high levels.

1.7.3 SULPHATES

Sulphates can be naturally occurring as a result of municipal or industrial discharges. They

occur naturally as a result of breakdown of leaves that fall into a stream of water passing

through rock soil containing Gypsum and other common minerals of atmospheric

decomposition. Sulphur is an essential plant nutrient and reduced concentration has a

detrimental effect on algae growth. The commonest form of sulphur in well- oxygenated

water is sulphate.

1.7.4 SALINITY

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This refers to salts dissolved in the water. The anions commonly present include CO₃²¯,

HCO₃¯, SO₄²¯, NO₃²¯, Cl ¯, PO₄ and F¯. The cations include; Ca²⁺, Mg²⁺, Na⁺ and K⁺. It may be

measured as TDS and is expressed in ppm units. It may also be measured by electrical

conductivity and is expressed as reciprocal micro ohms per cm (µomhs/cm). Salinity says

nothing about which elements are present but this may be of critical importance. So when

the salinity is elevated, the water should be analyzed for the specific anions and cations.

An abrupt change of water of high salinity to one of low salinity may cause animals harm

while a gradual change would not. Animals can consume water of high salinity for a few

days without harm, if they are then given water of salinity. The cations may have toxic

effects because of their solubility effect or interference with other elements. High salinity

levels may also be treated to physiological effects upon animals and plants exposed to the

water, corrosion and encrustation of equipment and detrimental effects on soil structure

and chemical fertility.

1.8 STATEMENT OF PROBLEM

Fosu Lagoon has suffered from large volumes of waste, both liquid and solid, from the final

disposal site at Nkanfoah in Cape Coast. Waste Oil, metals and other forms from garages at

siwdu, as well as the waste product from palm kernel extraction around Adisadel Village and

free-range defecation in the lagoon catchment area, had added to its current highly

contaminated state. Various individuals have conducted research to ascertain the extent of

pollution of the lagoon. The problem which keeps on lingering on the minds of people is

how to remedy the rate at which pollution is helping to degrade this natural habitat of some

fishes and organisms.

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1.9 OBJECTIVES

1.To identify specific existing or emerging water quality problems as a result of the presence

of different potential pollution sources and their particular waste-water management along

the banks of Fosu Lagoon

2. To gather information to design specific pollution prevention or remediation programs

3 To determine the water quality of the Fosu Lagoon through physical, chemical and

biochemical analysis

CHAPTER TWOMETHODOLOGY

2.1 STUDY AREA

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The Fosu lagoon is one of the most important closed lagoons in the central region of Ghana.

It is termed ‘closed’ because it is separated from the sea by a sand bar. This sand bar is

formed by the influence of the coastal wind regimes and long shore drifts. The Fosu lagoon

lies (5° 07’N, 1° 16’W) and covers an estimated area of 61ha. It has an average water depth

of 16cm and hence considered shallow (Blay and Asabre-Ameyaw, 1993)

The geology of the lagoons is a mud soil its salinity is relatively low (about 25%).

A glance at the mangrove community indicates that it has been extensively degraded due to

changes in the sedimentary environments, expect for a strand of Avicennia Africana and

Paspalum vaginatum near the Fosu shrine. The degradation of the mangrove community

has also resulted in the loss of roosting sites of some migratory birds. Also, large portions of

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the lagoon had dried up and were over grown with weeds which had also made it possible

for people to walk on it to dump garbage. Sediments are washed into the lagoon during

heavy rains owning to the fact that the vegetation that stabilizes the banks from erosion has

been removed (CCMA, 2007).

The lagoon is heavily polluted due to the inflow of effluents from surrounding settlement

(Washing bays and households).

It was observed that waste oil, metal scarps and other wastes from garbage and waste

generated from palm kernel extraction in siwdu have contributed to the contamination of

the lagoon among other negative human practices like defecating at the banks of the

lagoon.

Most of the indigenes of this community are either involved in fishing or fish processing

activities such as smoking, salting and fermenting of fish. The fishermen practice artisanal

fishery by use of cast nets and hook and also practice hand fishing. The main fish species

found in the Lagoon is Sarotherodon melanotheron. Sarotherodon melanotheron is relatively

eurythermal species and its temperature range in its natural habitat is about 18-33°C

(Philipart and Ruwet, 1982). No breeding occurs below 20-30°C (Trewavas, 1983). It

constitutes about 90% by weight of the total catch and annual yield of 452-664 kg/ha is

higher than those reported for other tropical lagoons (Blay and Asabre-Ameyaw, 1993). It is

gradually becoming the only fish species in the lagoon. This is because it is a hardy fish

species and it has prolific breeding habits.

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2.2 SAMPLE COLLECTION

The samples were collected along the banks and middle of the lagoon. The samples were

collected during a period of prolonged dryness and continued into the rainy season. The

duration of this exercise was eight weeks. The sample containers were washed in the

laboratory and rinsed with the sample water at the point of collection.

Containers were labeled with

Site

Time

Temperature

Date

2.3. SAMPLE TREATMENT/STORAGE

The samples were stored in a cool dry place till the analysis was completed. The samples

were collected with a plastic bucket from the lagoon and transferred into the labeled

bottles.

2.4 INSTRUMENTS/APPARATUS

pH meter (mettle Toledo MP 125)

Conductivity meter (Hach co 150)

Turbid meter (Hach CO 150)

Spectrophotometer (HACH DR/2000)

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2.5 REAGENTS/CHEMICALS USED

Standard Buffer for pH (4.0 and 7.0)

Phosver 3 phosphate reagent

Sulfaver 4 sulphate reagent

Distilled water

2.6 METHOD AND PRINCIPLE

The study methods used to collect data for this project included Personal Observations and

Surveys, Water Sampling and Analyses, Desk Study and Interviews. Water quality

parameters measured included pH, Temperature, Conductivity, Total Dissolve Solids,

Nitrates, turbidity, salinity, phosphate and sulphate. Institutions involved in the interviews

were Environmental Protection Agency, Institute of Renewable Natural Resources, Waste

and Sewerage Department, Ghana Water Company Limited and Ghana Statistical Service –

all based in the Cape Coast Metropolis.

2.7 Conductivity Meter.

The conductivity meter was first calibrated using the calibration constant solution. The

probes from the various conductivity meters were dipped into the calibration solution. The

units were calibrated by adjusting the value on the meter to read the value of the constant

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(0.1413 milli-siemens (mS). This was done by using either increase/decrease buttons on the

meter or using a small tool supplied with the meters to adjust a small potentiometer.

CALIBRATION OF THE METERS WITH pH 7 and Ph 2 buffers

1. Select the pH mode and set the temperature control knob to 25°C. Adjust the cal 2

knob to read 100%

2. Rinse the electrode with deionised water and blot dry using a piece of tissue

(Shurwipes or Kimwipe are available in the lab.)

3. Place the electrode in the solution of pH of 7 buffer, allow the display to stabilise

and, then, set the display to read 7 by adjusting cal 1. Remove the electrode from

the buffer.

4. Rinse the electrode with deionised water and blot dry using a piece of tissue

(Shurwipes or Kmwipes are available in the labs).

5. Place the electrode in the solution of pH 2 buffers, allow the display to stabilise and,

then, set the display to read 2 by adjusting cal 2. Remove the electrode from the

buffer.

6. Rinse the electrode with deionised water and blot dry using a piece of tissue.

2.8 ANALYSIS OF PARAMETERS

2.8.1 pH.

This was determined by first of all standardizing the pH meter with buffer solutions of pH

7.0 and pH 4.0. The electrode was rinsed with distilled water. The sample was put into a

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25ml beaker. The electrode was then put into the beaker. Then the meter switched on and

pH selected. The meter blinks until stable, and then the readings were taken.

2.8.2 CONDUCTIVITY, TDS and SALINITY

The conductivity meter was used in determining these parameters. It was standardized by

dipping its electrode into de-ionized water to ensure that it reads zero. The electrode was

then dipped into the sample and the respective parameters were read by switching to the

mode of each parameter.

2.8.3 TURBIDITY

This was determined by the turbid meter. The cell of the instrument was rinsed with

distilled water and filled to the given mark on the cell (5ml). This was then placed in the

cavity and the light shield closed. The instrument displays the reading after been switch on.

2.8.4 NITRATE

A pillow of nitrate reagent was added to 25ml of the sample in the cell. This was then

swirled to mix and then the concentration determined using the spectrophotometer.

2.8.5 TEMPERATURE

The temperature was determined with a temperature at the point of collection.

2.8.6 SULPHATE

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This was determined using the spectrophotometer. Sulfaver 4 sulphate reagent was added

to the sample and swirled gently to mix and its concentration determined on the

spectrophotometer.

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CHAPTER 3

TABLE OF RESULTS AND GRAPHS

3.0 RESULTS

TABLE OF RESULTS 3.1

The results obtained from the analysis of samples are presented in the table below

PARAMETERS JANUARY February March April Mean W.H.O

pH 9.03 8.70 9.19 8.87 8.95 6.5-8.5

TEMPERATURE/°C 30.30 31.33 30.67 31.33 30.90 VARIES

TURBIDTY/NTU 33.67 34.33 34.67 24.73 31.85 5

TDS/ppm 2.09 2.21 1.85 2.02 2.04 1000

SALINITY/‰ 2.40 1.33 1.67 0.14 1.385 0.1

CONDUCTIVITY/ppm 455.0 433.0 446.0 447.0 445.3 1000

PHOSPHATE/mg/l 2.90 1.30 2.61 1.40 2.05 0-0.4

SULPHATE/ mg/l 127.9 139.8 157.4 124.5 137.4 250

NITRATE/ mg/l 2.50 7.25 3.50 4.30 4.39 0.1-0.5

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VARIOUS LEVELS OF PARAMETERS STUDIED.

Figure 3.1

January February March April8.4

8.5

8.6

8.7

8.8

8.9

9

9.1

9.2

9.3

pH against month

26

Figure 3.2

January February March April29.6

29.8

30

30.2

30.4

30.6

30.8

31

31.2

31.4

31.6

Temperature /°C against month

27

Figure 3.3

January February March April0

5

10

15

20

25

30

35

40

Turbidity /NTU against Month

28

Figure 3.4

December January February March April0

1

2

3

4

5

6

7

8

9

TDS /ppm against Month

29

Figure 3.5

January February March April0

0.5

1

1.5

2

2.5

3

salinity/‰ against month

30

Figure 3.6

January February March April4.2

4.25

4.3

4.35

4.4

4.45

4.5

4.55

4.6

conductivity/ppm against month

31

Figure 3.7

January February March April0

1

2

3

4

5

6

7

8

NO₃¯ /mg/l against month

32

Figure 3.8

January February March April0

0.5

1

1.5

2

2.5

3

3.5

Phosphate/mg/l against month

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CHAPTER 4

Discussion

4.1 pH

The acceptable limit for pH is 6.5-8.5. The pH for Fosu lagoon was found to be slightly

alkaline and therefore could not support life of fishes in the lagoon. This was because; they

were above the acceptable limit. (I.e. 8.70-9.19). This could be attributed to the presence of

hydroxyl ions in the water.

4.2 TEMPERATURE

The temperature for Fosu lagoon was within the range of (30.30-31.33). The water body is

said to be warm. This could be attributed to the direct heating from the sun and also due to

the landscape. There could also be a lot of dissolved substances in the lagoon. Temperatures

such as that of Fosu Lagoon supports more plant life and fishes like bass, bluegill, carp,

catfish, leeches, caddis fly.

4.3 TURBIDITY

The turbidity for Fosu Lagoon was below the acceptable limit of (500mg/l-1000mg/l). The

range fell within (24.73mg/l-34.67mg/l). Turbidity measures the cloudiness of a body of

water. This could be attributed to the presence of suspended materials such as sand, clay,

silt etc. This covers sunlight from reaching the bottom of the lagoon. Oil spillage from the

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Siwdu and some effluent from the Palm kernel plant at Adisadel could be a contributing

factor to the high rate of turbidity in the lagoon.

4.4 TOTAL DISSOLVED SOLIDS and CONDUCTIVITY

Although Fosu Lagoon is not a drinking water, TDS is used to estimate the quality of drinking

water, because it represents the amount of ions in the water. Water with high TDS often has

a bad taste and/or high water hardness, and could result in a laxative effect.

Hardness mitigates metals toxicity, because Ca2+ and Mg2+ help keep fish from absorbing

metals such as lead, arsenic, and cadmium into their bloodstream through their gills. The

greater the hardness, the harder it is for toxic metals to be absorbed through the gills.

Because hardness varies greatly due to differences in geology, there are no general

standards for hardness. The hardness of water can naturally range from zero to hundreds of

milligrams per liter (or parts per million).

Water hardness has a connection with the conductivity of the water. Conductivity

determines the amount of charged particles in a water sample, therefore, the harder the

water sample the higher its conductivity.

The TDS as well as the conductivity of the Fosu Lagoon were high and thus likely to pose

some danger to the aquatic life. The filthiness of it is because of the high suspended solids

caused by dumping of refuse from domestic homes. It renders the Lagoon unworthy for any

recreational purposes. Dirty oils from the fitting shops around the Lagoon poisons the fishes

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in it, this affects the human health, because the fishes caught in the Fosu Lagoon are mainly

for human consumption.

4.5 PHOSPHATE

The acceptable limit is 0.3 mg/l. The phosphate levels for Fosu lagoon were above the

acceptable limit. (I.e. 1.30-2.61). This explains why weeds and aquatic plants are found on

the Fosu lagoon.

4.7 SULPHATE

The acceptable limit is 400mg/l. The level of Sulphate in Fosu Lagoon was within the range

of 124.5-157.4. Sulphates at a concentration of about 250ppm can have a laxative effect on

people. High levels of sulphates form slimes, encrustations and odorous water.

4.8 NITRATE

The acceptable limit for nitrate in drinking water is 10mg/l. The range of nitrate in Fosu

Lagoon was 2.50-7.25. Nitrates impart a bitter taste to the water at levels of 20-50ppm.

Nitrate levels of about 25ppm often indicate contamination of water bodies from human

sources such as human waste, inorganic compounds and chemical fertilizers. Nitrates are

converted within the body to nitrites by bacteria action.

4.9 SALINITY

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The recommended W.H.O value for salinity ranged from 0.0 to 0.1% of NaCl. The salinity for

the lagoon ranged 0.14 and 2.14. This means the lagoon is more salty. It indicates the

intrusion of sea water into the lagoon.

CHAPTER 5

5.1 CONCLUSION

From the Analysis, it can be deduced that, most of the pollutants in the Fosu Lagoon are as a

result of;

Wrong sitting of facilities such as building the district hospital close to the Lagoon

and the garages at Siwdu.

lack of demarcated sites for refuse disposal

relatively inaccessible refuse dump sites

lack of awareness of the health implication of insanitary practices

indifference to the presence of waste

lack of the requisite equipment for disposal

poor siting of refuse disposal sites (e.g. along river banks and marshy areas, near

water sources)

lack of the technical know-how to add value to waste (e.g. composting)

5.2 RECOMMENDATION

There is the need for an enforcement of aquatic pollution control in our nation and

in particular Fosu Lagoon to ensure the;

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1. Protection of Fishes and other aquatic organisms.

2. Effects on the environment and the human health.

3. Protection of the coastal areas and the use for recreational purposes

There should be a local legislation on the management of Fosu Lagoon. Such

Pollution Control measure should defined those technical, administrative and legal

steps needed to check, regulate, reduce, remove or eliminate, within certain limits,

the undesirable effects of the presence of certain substances in waters minimize

those activities that results in the alteration of the physical, chemical, microbiological

or aesthetic properties of the lagoon.

Fishing is a means of survival for the study population contributing to lower

perceived risk. The value of fishermen understands of the environment and fishing

practices may not be enough to help reduce their exposure to risk of eating polluted

fish. Therefore educational programs based on the importance of tradition,

experience and scientific information may be an appropriate intervention

A cost-benefit analysis on the fencing of the lagoon should be carried out to

ascertain the importance of fencing the lagoon. One importance to nature will be to

allow the lagoon to get rid of some pollutants through Biodegradation.

The garage at Siwdu should as a matter of urgency be re-settled at another place and

this needs the involvement of city authorities, traditional authorities and the

managers of the garage.

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Whilst infrastructural initiatives to deal with bulk pollution will be required, for

example improved sewage treatment systems, actions at the individual and

community levels are also desirable

REFERENCES

1. A.S Mather and K. Chapman “Environmental Resources” Longman Scientific and

Technical UK pp 183

2. http//www.troz.uni-hohenheim.de/research/Thesis/MScEE

3. http://en.wikipedia.org/wiki/Water_pollution

4. The Royal Society “The nitrogen Cycle of UK” Report of the Royal Society study

group. Royal society London.

5. World Health Organization “Sodium Chlorides and conductivity in drinking water”

Report on AWHO working group. Euro reports and studies 2, Regional office for

Europe Copenhagen (1979).

6. D.C Whitehead “Grassland Nitrogen” Biddles Ltd, Guild ford UK pp (11)

7. Evelyn Hutchison “A treatise on limnology. Vol. 1 Geography, Physics and chemistry”

pp 738-744

8. Smith Enger “Environmental Science” WCB. McGraw-Hill, Inc. 1998 2nd edition

Chapter 7

9. G.N Somero, C.B Osmond C.L Bolis (Eds), Water and life.

10. Vogel’s Textbook of quantitative chemical analysis, 5th Edition Pg 519-521.

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11. Raymond J.et al “Water resources instrumentation” International Water resources

Ass.

12. http://epa.gov/bioiweb1/aquatic/pollution.htm

13. N.J.H Geurink, Matestain, A. Kemp “Nitrate poisoning in cattle prevention”

Netherlands journal of Agriculture Science pp 30, 105-113

14. Water quality assurance. “Monthly Report” Ghana water company, Cape Coast

15. USEPA; Advance Notice of proposed rule Making, Federal Regulation (136), pp 2899

16. P.N.D.C Law 305 cb, Food and drugs Law 1992, Ghana Publishing Corporation.

17. Guidelines for drinking water quarterly W.H.O Recommendation Volume 1, 2,

1984criteria for water, U.S. EPA, July, 1976

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